1. Technical Field
The present invention relates generally to wireless communication networks and in particular to Quality of Service (QoS) within wireless communication networks. Still more particularly, the present invention relates to a method and system for providing a QoS-based link layer protocol within the air interface of a wireless communication network.
2. Description of the Related Art
The demand by consumers all over the world for wireless services continues to expand at a rapid pace and is expected to continue. Two major developments in the wireless industry are the introduction of multi-carrier transmission capabilities and support for data services in addition to the traditional voice services.
Within a wireless network, enabling communications between a base station and mobile unit involves various hardware and software components and implementation of a transmission protocol to define the characteristics of the communication. The transmission protocol typically manages different operations of the communications process including interaction between the protocol stack/layers, (i.e., physical, data, and network layers etc.). The protocol implemented also determines the efficiency with which the network is able to support multi-carrier operations and manage multiple application data streams simultaneously.
The developments within the industry led to the introduction of the third generation (3G) technology standards. One key aspect emphasized within 3G systems is quality of service (QoS). Third generation wireless networks need to support a wide range of applications that may require very different over-the-air QoS delivery. Most current wireless networks operate with a Radio Link Protocol (RLP) controlling the packet data transmission over the air interface between network communication units. The RLP, for example, provides for the reliable transfer of data across the physical link, such as sending blocks of data with the necessary synchronization, error control, flow control, and so forth. However, RLP has several limitations that directly affect efficient 3G network implementation.
For example, RLP was designed for providing simple error recovery and is not able to meet the increasing demand efficiently. Also, the existing RLP is inefficient in supporting multiple applications having different QoS requirements: Thus, multiple RLP instances are required to support multiple applications when the applications have different QoS requirements. Each RLP operates independently, and cannot take advantage of the existence of other RLP instances. For example, each idle RLP needs to send “keep-alive” packets to maintain its synchronization even when another RLP is fully active.
Adding/removing a QoS data stream within an RLP instance incurs a significant amount of overhead because network resources have to be allocated and the RLP has to go through a new synchronization process. This is troublesome for bursty packet data support where applications may be launched and terminated rather frequently.
Other limitations exists with RLP implementation. RLP has limited support for priority marking. (The marking actually happens outside of the RLP). RLP does not have a mechanism to support dynamic Layer 2 (data link) to Layer 1 (physical) mapping which is essential in the multi-carrier, adaptive modulation and coding air interface environment.
Unfortunately, service support with current 3G systems still rely on traditional Radio Link Protocol (RLP) (within the communication protocol stack) to provide the over-the air interface for these new services. As noted above, this reliance has held back further development in 3G technology.
The present invention recognizes that it would be desirable to provide a method and system for implementing a QoS-based RLP that enables dynamic QoS support for multiple applications requiring air-interface links with different QoS requirements. A method and system for eliminating the problems associated with RLP in dealing with placing/supporting multiple simultaneous applications over the air transmission interface would be a welcomed improvement. These and other benefits are provided by the invention described herein.